Slant-hole collimator, dual mode sterotactic localization method

Abstract

The use of a slant-hole collimator in the gamma camera of dual mode stereotactic localization apparatus allows the acquisition of a stereo pair of scintimammographic images without repositioning of the gamma camera between image acquisitions.

What is claimed is:  
     
       1. In a mammographic examination system comprising: 
       A) a table;  
       B) an aperture in said table to receive the breast of a female patient lying on said table;  
       C) at least one paddle below said aperture oriented to compress said breast for purposes of mammographic examination;  
       D) an X-ray generator and an X-ray detector movably located below said table and providing the ability to produce a stereo pair of X-ray images of said breast; and  
       E) a movable scintimammography camera including a collimator, said scintimammographic camera being removable from the field of view of said X-ray detector when said stereo pair of X-ray images is being produced and placed in proximity with said paddles to provide a stereo pair of scintimammography images that can be registered with said stereo pair of X-ray images to provide a dual mode stereotactic localization apparatus, the improvement comprising the incorporation of a slant-hole collimator as the collimator.  
     
     
       2. The dual mode stereotactic localization apparatus of  claim 1  wherein said slant hole collimator includes collimator holes at an angle of about 15° from orthogonal. 
     
     
       3. The dual mode stereotactic localization apparatus of  claim 1  wherein said X-ray generator is mounted on a rotatable support arm. 
     
     
       4. The dual mode stereotactic localization apparatus of  claim 3  wherein said scintimammography camera comprises: 
       A) a slant-hole collimator;  
       B) behind said slant-hole collimator a scintillator array positioned to receive gamma radiation from said collimator;  
       C) a light guide positioned to receive visible light emitted by said scintillator array and transmit it to;  
       D) an array of photomultiplier modules each individually connected to;  
       E) a resistive electronic circuit comprising a high voltage supply and an amplifier for generation of a digital image.  
     
     
       5. The dual mode stereotactic localization apparatus of  claim 4  wherein said slant-hole collimator includes collimator holes at an angle of about 15° from orthogonal. 
     
     
       6. The dual mode stereotactic localization apparatus of  claim 4  wherein said array of photomultiplier modules comprises a two by two, square array of four photomultiplier modules. 
     
     
       7. The dual mode stereotactic localization apparatus of  claim 6  wherein said array of photomultiplier modules measures about 4″×4″. 
     
     
       8. The dual mode stereotactic localization apparatus of  claim 6  wherein said scintillator is selected from the group consisting of CeI(Tl), CeI(Na), NaI(Tl), YAP, YSO, GSO, LSO and LGSO. 
     
     
       9. A dual mode method for the stereotactic localization of potentially cancerous lesions comprising the steps of: 
       A) injecting a patient to subjected to examination with a suitable radiopharmaceutical;  
       B) placing said patient face down on a dual mode stereotactic examination device comprising:  
       1) a table;  
       2) an aperture in said table to receive the breast of said female patient;  
       3) at least one paddle below said aperture oriented to compress said breast for purposes of mammographic examination;  
       4) an X-ray generator and an X-ray detector movably located below said table and providing the ability to produce a stereo pair of X-ray images of said breast; and  
       5) a scintimammography camera also mounted below said table that is removed from the field of view of the X-ray detector when said stereo pair of X-ray images is being acquired and placed in proximity with said paddles to provide a stereo pair of scintimammography images said gamma camera including a slant-hole collimator;  
       C) producing said stereo pair of X-ray images of said breast by exposing said X-ray detector to X-rays produced by said X-ray generator through said breast from two different positions while said moveable scintimammography camera is out of the field of view of said X-ray detector;  
       D) placing said scintimamography camera in proximity with said paddles;  
       E) producing a stereo pair of images with said scintimammography camera by exposing said breast to said scintimammography camera from a single angle but before and after rotating said slant-hole collimator 180°; and  
       F) registering said X-ray stereo pair of images and said scintimammography camera stereo pair of images.